The present invention relates to a method and apparatus for heating and/or drying flowable loose material, preferably granular polymeric material, that is to be conveyed to a processing machine, preferably an injection molding machine.
During the processing of granular polymeric material, it is known to dry the granulate prior to feeding it to the processing machine. For this purpose, the granular polymeric material is temporarily stored in a drying hopper through which drying air flows from the bottom toward the top. As soon as the granular polymeric material is dried, it is conveyed to the processing machine. The drying temperature, however, is less than the desired material temperature at the inlet to the processing machine, which is generally an injection molding machine where the granular polymeric material is processed with a plasticizing conveyor screw. In this connection, considerable energy must be applied in order to be able to convert the granular polymeric material into the plasticized state. The energy requirement is correspondingly high, and the heating-up time is relatively long.
It is therefore an object of the present invention to provide a method and apparatus of the aforementioned general type whereby, however, the flowable loose material can be dried with little expenditure of energy within a very short period of time.